[[quoteright:350:http://static.tvtropes.org/pmwiki/pub/images/international_date_line_5227.jpg]]

->''"Fell asleep on Tuesday, woke up Monday afternoon''
->''I slept right through your International Date Line"''
-->--'''The Ataris''', [[https://www.youtube.com/watch?v=Z-RTvz6OETU "Takeoffs and Landings"]]

AsYouKnow, the Earth is round, and it makes a complete rotation every 24 hours. [[note]]Actually 23 hours, 56 minutes, 4.06 seconds -- The 24 hours (approximately) is the time between moments when the sun is directly overhead at some point on a given longitude, and since the Earth is revolving around the sun as it rotates, this requires a little more than one rotation.[[/note]] Back when they were formalizing time zones, they had to decide at which point the official transition between one day and the next happened.

This was SeriousBusiness. Wars have been fought over it. For early travelers, the international date line was an almost mystical zone in which a small-scale form of TimeTravel was possible. For murder mysteries, an alibi can be made or broken by such a date line.

Crossing this in a ship is grounds for, if you're in the Royal Navy or the United States Navy, [[InitiationCeremony being "dowsed" in batter, "shaved", made to drink a mixture that includes chilli sauce and dunked in water.]]

Historically, the line has found itself moving as politics changed. Alaska, for one, used to be on the same 'day' as Russia ... up until it was bought by the United States, of course. Kiribati was a nation on the west side of the line when it gained independence, until it gained some land on the east. Eventually they just declared the whole thing on the west side (and touted it when 01 Jan 2000 was coming up). Most recently, Samoa and Tokelau both switched from being on the east side to the west side, completely skipping over 30th December 2011. Future revisions may or may not happen.

Note that the date line is mainly an abstract idea. The real 'line' that separates one day from another is when midnight swings by your time zone; thus, when it's 0:00 in Chicago, the date line is really there. And everywhere else that observes UTC -6 (during 'Standard Time') or -5 (during Daylight Savings Time). This tends to draw big celebrations on New Year's Day and any big media release.

It [[IThoughtItMeant absolutely does not refer to]] [[IncrediblyLamePun a phone number you call to set up dates with foreigners]].
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!!Examples:

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[[folder: Anime and Manga ]]

* The Molmol Kingdom from ''LoveHina'' is stated to be placed exactly on the International Date Line. This, of course, becomes a plot point when Keitaro has to return to the Hinata Inn before a certain date.
* ''Anime/SpeedRacer'': In "The Little Grand Prix" two-parter Pops builds a racecar for a prince to run in an 8-12 year olds race. Spritle wants to be in the race too but his 8th birthday is the day after the race. At the end of the episode, they realize that they're on the other side of the date line meaning that Spritle is 8 years old ''today''. So Pops whips up a car for Spritle to race in. He and the Prince come in first & second.

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[[folder: Film ]]

* Subject of a snarky comment in ''[[Film/{{Gremlins}} Gremlins 2]]'', when some characters are questioning the vagueness of the "don't let the mogwai eat after midnight" rule.

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[[folder: Comic Books ]]

* There's a DonaldDuck story by Creator/DonRosa where Scrooge and Flintheart Glomgold try to claim ownership to a newly formed island that's located directly on the International Date Line. The fact that one half of the island has a different weekday than the other becomes a plot point when it comes to determining who claimed it first. [[spoiler:It was actually Scrooge's guide, who did it without knowing it]].

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[[folder: Literature ]]

* ''Literature/AroundTheWorldInEightyDays'' - The protagonists think they have lost the bet, but it turns out they were right on time since they had forgotten to account for crossing the international date line.
** Note that the novel takes place in 1872, and time zones weren't officially standardized--or the International Date Line established--until the International Meridian Conference in 1884. So Mr. Fogg's failure to notice the date change isn't quite as boneheaded as it seems. (Although you do have to wonder [[FridgeLogic how he managed to cross America by train without knowing what day of the week it was]].)
** This gets mentioned any time you do a WholePlotReference to this story.
*** The ''StrawberryShortcake'' episode "[[AroundTheWorldInEightyDays Around the Berry Big World]]" uses this. It's even lampshaded, as the episode begins with Strawberry giving a book report on the story and specifically mentioning how Fogg won.
*** And done again in ''Film/TheThreeStooges Around the World in a Daze''. Except it's Fogg's decendent, as it's set in the same time (and with the less than bright idea of having the Stooges as wait staff). [[spoiler:And this Fogg makes ''the same error''.]]
* ''The Island of the Day Before'' by Umberto Eco takes place on the international date line, or at least its characters believe that it does--since they're marooned on a ship in an era before TheLongitudeProblem was definitively solved, it's tough to know for sure. The characters spend a great deal of time discussing it, often in excessively confused ways (e.g., the Jesuit priest declares that all the extra water required for Noah's flood to cover the land came over the date line from yesterday).
* The Creator/EdgarAllanPoe short story "Three Sundays In A Week": The protagonist's guardian says he can get married [[CueTheFlyingPigs when there are three Sundays in a week]], and by inviting over two sailors who have just circumnavigated in opposite directions, he manages to meet the condition.
** In fact, with Creator/JulesVerne being a great Poe fan, this story directly inspired ''Literature/AroundTheWorldInEightyDays'', up to a marriage subplot.
* ArthurCClarke's short story "Trouble With Time" is set in a city that was built on the international date line of the planet Mars for some reason. A man tried to rob a priceless artifact from a museum and was caught by the staff when they opened up for the morning. He thought it was Sunday morning (When the museum would be closed) because that's what day it was in the part of the city where his hotel was located, but in the part of the city where the museum was, it was Saturday morning. ''Avoiding'' confusing situations like this is the reason why the international date line of Earth was placed in the middle of the Pacific Ocean and zig-zags around to not touch any land masses.
** Putting the problem in the middle of the ocean obviously isn't an option on Mars, but it would be even easier to just have the date line run between domed cities and not through the middle of one of them.

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[[folder: Live Action Television ]]

* It was mentioned in Creator/MichaelPalin's first TravelogueShow, ''Around the World in 80 Days''. Like in the Navy Initiation ceremony mentioned above, Michael participated in a rather surreal initiation ceremony on the cargo ship he crossed the dateline on
* Discussed in an episode of ''Series/PowerRangersSPD''. Bridge, the Green Ranger, doesn't know exactly what day his birthday is because he was born on an airplane as it was going over said date line.
* An episode of ''[[Series/TheSuiteLifeOfZackAndCody The Suite Life on Deck]]'' had Cody trying to impress Bailey at the school dance, and suddenly getting stuck in a GroundhogDayLoop because of [[LightningCanDoAnything lightning]] striking the ship as it crossed the International Date Line.
* In a season 2 episode of ''Series/TheWestWing'', the President flies home from Tokyo and winds up traveling back in time.
-->'''Josh''': He's going to land in Washington an hour before he took off?
-->'''Sam''': Yeah.
-->'''Josh''': And [[WorstNewsJudgementEver that's not a story]] that beats the [[DrugsAreBad Surgeon General]]? [...] The man's going 150 hours, how can it be Thursday the whole time?
* One episode of ''Series/{{Benson}}'' (from when the title character was lieutenant governor) had him presiding over a conference of Pacific Island heads of state when two of them (ex-lovers) got into a shouting match. While trying to piece together what happened, it's revealed that Kraus was responsible for the leaders from one side of the International Date Line and Clayton was responsible for the other. Clayton sent Kraus a memo to remove one of the two from the invitations, but she ignored it. It was later revealed that they were to be married, but neither showed up at the church at the same time as the other. It turned out that due to both countries being on opposite sides of the Date Line, one was at the church a day early while the other was there a day late.

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[[folder: Magazines ]]

* One ''Reader's Digest'' had a story in "Humor In Uniform" where a naval officer committed a serious offense, got demoted, and lost his pay. However, he was not terribly bothered because his birthday was coming up. Right up until he went to bed the night before his birthday, he smugly expected the crew's obligation to celebrate his birthday. The next morning, he woke up and discovered that the ship had crossed the International Date Line during the night and it was now the day ''after'' his birthday.

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[[folder: Newspaper Comic ]]

* In a ''ComicStrip/{{Dilbert}}'' comic, the PointyHairedBoss asked for questions, saying that "there are no stupid questions". He changed his mind when someone asked "If you crossed the International Date Line on your birthday, would you still get presents?"

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[[folder: Real Life ]]

* Real life: ''Line Aquavit'' is a Norwegian specialty in which aquavit is matured in sherry casks stored aboard ships that run from Norway to Australia and back, crossing the International Date Line in the process. The combination of the ship's motion and the trip across the Line supposedly give the aquavit a unique flavor.
** While the specifics of its effect on the aquavit are debatable, the tradition of aging wine and spirits in barrels on a long ship journey is at least 400 years old, dating back to when fortified wine would be hauled on Dutch East India Company ships from Madeira to Indonesia before going back to mainland Europe, giving us what we know as Madeira wine.
* The log of an American PBY bomber that crossed the Date Line twice during the [[UsefulNotes/WorldWarII Battle of Midway]] records that it took off on June 3, attacked the Japanese on June 5, and landed back at its base on June 4.
* If you manage to cross the International Date Line when it's locally midnight, you can either experience a full calendar day twice in a row or skip it entirely, depending on whether you're flying east or west.
** So,yes, the Navy can take away your birthday, or Christmas.
* A F-22 squadron [[http://www.defenseindustrydaily.com/f22-squadron-shot-down-by-the-international-date-line-03087/ experienced a major software crash]] when they crossed the date line, causing most systems to freeze. Fortunately they were able to make it back to base by following their refueling tanker.
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